1. Field of the Invention
The present invention relates generally to engine controllers and, more particularly to, a power supply for a single board engine controller.
2. Description of the Related Art
The energy crisis of the 1970's has forced automotive engine designers to turn to computer technology to improve fuel economy. Today, sophisticated on-board computers, called engine controllers, monitor engine-related operating variables such as intake and exhaust manifold temperature and pressure, engine temperature, coolant temperature and pressure, throttle position, engine timing, air and fuel flow, engine RPM, transmission gear selection, ambient pressure and temperature, as well as other operating variables. The engine controller uses the data from these operating variables to maximize engine performance, increase efficiency and minimize exhaust emissions under a variety of engine operating conditions.
Generally, the engine controller includes a power supply which has the demanding task of supplying the controller with the proper amount of electric power under greatly varying engine operating conditions. As such, the power supply must be able to regulate power under high and low load conditions on the engine controller. The power supply must also have the capability of supplying enough power to the engine controller for engine ignition to occur. The power supply relies totally on a vehicle battery for its source of power and, therefore, must be able to regulate its output voltage when the vehicle battery voltage is as low as 4.5 wHs (cold start voltage) and when the vehicle battery voltage is as high as 24 volts (series battery jump start). Typically, conventional timer pulsed power supply circuits are unable to vary the position of the output voltage pulse throughout the wide range of frequencies required in applications for the engine controller to provide adequate power regulation. Thus, there is a need in the art to provide an engine controller power supply which can supply adequate power during low battery voltage engine startup and precise regulation during high battery voltage engine startup. Also, there is a need in the art to provide a pulsed power supply for an engine controller.